Re: [RFC PATCH] x86/vdso/32: Add AT_SYSINFO cancellation helpers

[Andy Lutomirski]

On Wed, Mar 9, 2016 at 1:19 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> On Wed, Mar 9, 2016 at 9:58 AM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>> On Tue, Mar 8, 2016 at 5:24 PM, Andy Lutomirski <luto@xxxxxxxxxx> wrote:
>>> musl implements system call cancellation in an unusual but clever way.
>>> When a thread issues a cancellable syscall, musl issues the syscall
>>> through a special thunk that looks roughly like this:
>>>
>>
>> FWIW, this patch fails disastrously on 64-bit kernels.  I fixed it,
>> but it needs kbuild changes.  I'll send those out to the maintainers.
>
> This version should be okay:
>
> https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/commit/?h=x86/vdso&id=fed6d35d3941bc53896ab80b5c8d68d54cc00347
>
> You'll need the parent, too, if you want to test.  I'm going to give
> the 0day bot a good long chew, since the parent change is a little bit
> scary.

Nope, that version was also not okay.  But the version currently in
that branch has survived the kbuild bot for a while now.

Yikes our build process for usermode code sucks.

--Andy